Atlantic Season Winds Down; Monitoring the Western Caribbean Long-Term

The second to last month of the 2017 Atlantic season winds down. On Saturday there are no areas of interest and no tropical cyclone development is expected over the next 5 days. A tropical wave in the western Caribbean stirs up convection near Central America. Pressure will stay general slow in this area for the next several days.

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Long-range computer models have been back and forth on possible development in the western Caribbean at the end of October or early November. The 0Z Euro shows no signs of an organized area of low pressure in the southwest Caribbean through Thursday October 26th. The 06Z GFS also shows no sign of tropical depression development.

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We’ll keep an eye on this region over the next 5-10 days. Looking ahead to November, tropical cyclone development is less likely, but not unheard of. Five percent of named storms form in the last month of the Atlantic season. November Climatology shows any activity typically forms in the western Caribbean and drifts northeast.

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Quiet Stretch in the Atlantic

Time ran out for Invest 92L east of the Bahamas. Wind shear is on the rise Tuesday as a cold front approaches. Upper level winds are not conducive for tropical development in the days ahead as this feature merges with a frontal boundary.

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No tropical development is expected for the next 5-7 days. The ECMWF shows no areas of concern through next Sunday. The long-range GFS hints that the western Caribbean is worth watching next week. It’s a ways off, but this makes with climatology.

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Ex Hurricane Ophelia Lashes Ireland; Invest 92L May Pass Near Bermuda

Former Hurricane Ophelia brought heavy rain, gusty winds, and coastal flooding to Ireland Monday. It is the strongest storm of its kind to hit Ireland since Debby in 1961. The core of the non tropical low moved ashore in southwest Ireland Monday morning EDT. According to the Irish Meteorological Society a gust of 97 mph was reported in Roches Point Co. Cork. Fastnet Rock, about 4 miles offshore of the coast, saw a gust of 109 mph. The remnants of Ophelia will brush the western United Kingdom late Monday EDT.

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Closer to home Invest 92L shows some signs of life early Monday. The area of low pressure east of the Bahamas is broad in nature, but it is producing wind gusts near tropical storm force. Convection increases early Monday under moderate westerly shear. Upper level winds become even less conducive for development mid-week as Invest 92L lifts northward and merges with a frontal boundary. This energy may pass near Bermuda late Tuesday. If this feature gains tropical characteristics it will called Philippe.

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Upper level winds become less favorable for organization of Invest 92L Tuesday and Wednesday. Notice all the red indicating high shear around the southeast U.S.. These hostile upper level winds shift east into the western Atlantic mid-week. The graphic below is courtesy NOAA/The University of Wisconsin at Madison.

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Ophelia Headed For Ireland; Watching Caribbean Disturbance

Ophelia became the 10th consecutive hurricane of the hyperactive 2017 Atlantic hurricane season mid-week over the north Atlantic. It is rare for hurricanes to form this far east. On Saturday morning Ophelia is the furthest east Atlantic major hurricane in history. This is according Dr. Phil Klotzback of Colorado State University. Ophelia is the sixth major hurricane of the season. As 11 AM EST Saturday max sustained winds are at 115 mph. The core of the storm will pass south of the Azores Saturday evening and early Sunday, but squalls will reach the Southeast Azores. Ophelia will transition to a non tropical system over cooler waters as it approaches Ireland Monday. While it will be an extra tropical system during this time, it will still bring tropical impacts. Hurricane force wind gusts and heavy rainfall are likely Monday and early Tuesday EST.

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We’re also watching a broad area of low pressure near the Leeward Islands. Upper level winds are hostile in the short-term. As of Saturday morning there is a 40% chance this becomes a tropical depression/Tropical Storm Philippe over the next 5 days. It may pass near Bermuda this work week, but is no threat to the U.S..

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Nate Lashes the Gulf Coast; Weakens Rapidly Inland-A Big Rainmaker For Some

Nate become the 4th hurricane of the hyperactive 2017 season to strike the U.S. (including Puerto Rico) this weekend. The last season with four or more U.S. landfalling hurricanes was 2005. It made two landfalls.The first near the mouth of the Mississippi River Saturday evening, the second near Biloxi Mississippi at 1:30 AM EDT Sunday as a category 1 hurricane with 85 mph.winds. The heaviest rain, strongest wind, and greatest storm surge was felt near and just east of the center.

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Nate will be remembered for its coastal flooding, a threat often underestimated with tropical system. A storm surge of 6.3 feet was recorded in Pascagoula Mississippi. Social media was blasted with photos and video of flooding in the Golden Nugget Casino in Biloxi. Mobile Alabama was also hit hard with coastal flooding. A storm surge of 5.4 feet was recorded there. The graphic shows the rise in water in Pascagoula, Mississippi  courtesy NOAA.

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Nate weakens rapidly Sunday morning over land. As of 11 AM it is a tropical depression. Max sustained winds are at 35 mph as it races north-northeast at 24 mph. It will weaken to a tropical depression Sunday. Nate is big rainmaker for portions, of the Southeast, Tennessee Valley, and eventually the Northeast U.S through Monday.

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Here is the 11 AM forecast track from the NHC. Nate will quickly lose tropical characteristics over the next 24-36 hours.

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3-6 inches of rainfall, with isolated high amounts are expected from central Gulf coast up through the southern Appalachians. The Weather Prediction Centers estimates 7-8″+ are possible in spots. This train of moisture brings heavy rain the Tennessee Valley and the Northeast U.S. too. Here are rainfall estimates from the Weather Prediction Center through Tuesday morning.

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Tropical Depression 16 Forms-To Become Nate; Headed For the Gulf This Weekend

Tropical Depression 16 forms in the southwest Caribbean at 11 AM Wednesday and an upgrade to Tropical Storm Nate is likely. Hurricane Reconnaissance Aircraft are en route to investigate the new tropical cyclone midday Wednesday. The data from the afternoon mission will be ingested into Wednesday evening computer models. This data is much needed, as Nate will threaten the northern Gulf coast, including Florida, as a strengthening storm. A hurricane is on table at this point.  As we’ve seen multiple times this season, systems are prone to strengthen rapidly this year. Water temperatures in the future path of Nate are in the low to mid 80s. Wind shear remains favorable for steady intensification in the Caribbean. By the time future Nate enters the Gulf late Friday/early Saturday, hostile upper level winds maybe much lower too. Interest along the northern Gulf coast from Louisiana to Florida need to pay close attention to the forecast, as a Gulf landfall appears likely. It is too early to talk specifics, but heavy rain, strong winds, spin up tornadoes, and storm surge are all expected. Even if Nate makes landfall west of Tampa Bay, the flood prone area is on the messy east side of future Nate. A southwest wind would induce coastal flooding/storms surge, as was the case with Hermine in 2016.

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There is quite a spread in Wednesday morning computer models. This is very common, with a weak, newly formed tropical depression. The time frame for greatest Gulf coast impacts will be Saturday and especially Sunday. Coastal Louisiana to the Panhandle of Florida are all on the table for a possible landfall. Intensity is still in question too. The GFS is further west than the ECMWF. The GFS hints at Louisiana while the Euro eyes the Florida Panhandle. Stay tuned and informed.

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Watching Invest 90L in the Caribbean; Headed for the Gulf by Saturday

While there are no named storms Tuesday, it looks increasing likely that Tropical Storm Nate will form in the Caribbean over the next few days. A broad area of low pressure, now pinned Invest 90L forms in the southwest Caribbean. Wind shear is incredibly high in the Gulf and portions of the western Caribbean. It is much lower in the southwest Caribbean near Invest 90L. This favors gradual organization. Invest 90L will lift northward through the end of the work week. While upper level winds will be elevated during this time, water temperatures are plenty warm for tropical cyclone development. Invest 90L heads for the Gulf of Mexico by Saturday morning. It is too early to say where future Nate will head, but interest in the northern Gulf coast from Louisiana to Florida need to stay informed.

Also of note is tropical wave near Cuba and southeast Florida. High westerly shear keeps the slug of moisture disorganized as it moves westward. It has a low chance of become a tropical depression/named storm over the next 5 days. Regardless of tropical development, wind gusts could approach weak tropical storm force in south Florida through Thursday. Heavy rain is also likely through late work week.

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As high pressure slips east in the Atlantic, future Nate lifts northward in the Gulf of Mexico and threatens the northern Gulf states Sunday and Monday. The European model has trended a little stronger over the past 24 hours. As of Tuesday afternoon, it suggest a hurricane moves into the Florida panhandle Sunday night. The GFS isn’t as strong as the EURO. It’s also further west with a coastal Louisiana track. Intensity and track will likely change in the coming days. There is no center or circulation for models to initialize on just yet. One thing for sure is we’ve seen how named storms can strength rapidly this season, if the upper level winds are favorable.

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This is why October is a vulnerable month for Florida and Southeast U.S.. Water temperatures are still in the low to mid 80s, which is plenty warm for storms to strengthen. Much of these waters have been untouched by named storms this season.

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The RPM model/Futurecast shows the tropical wave near Florida moves in the Gulf Thursday and Friday. As it does so, it yanks tropical moisture over south Florida.

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Watching the Caribbean Later This Week

After a hyperactive September, our focus shifts to the Gulf of Mexico, Western Caribbean, and extreme Western Atlantic in October. While 17% of named storms form during the second to last month of the Atlantic season, systems that form in this region often drift towards Florida and portions of the Southeast U.S..

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For more than a week, models have hinted that pressure may lower in the Western Caribbean in early October. On Monday, an upper level low stirs up convection near the Yucatan. A surface low may attempt to form in this region later this work week.. For now, those odds are low over the 5 days. This future area of disturbed weather could move into the southern Gulf of Mexico by Friday or Saturday.

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As is always the case with a developing tropical cyclone, computer model are all over the place. The European model hints that Tropical Storm Nate may approach the west coast of Florida Sunday or Monday. Wind shear may be high enough to keep anything that forms weak. Interest in Florida and the northern Gulf coast should continue to check back in.

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Meanwhile, the latest GFS backs off on any tropical depression/tropical storm development. It’s watch and wait situation in the days ahead.

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Florida Low Unlikely to Develop; Wet Weekend For Florida

A weak area of low pressure we’ve been watching for a few days, Invest 99L, is increasingly unlikely to gain any tropical characteristics over Florida. In combination with a cold front and nearby upper low, the area of low pressure enhances showers and storms this weekend in north central and central Florida. As high pressure builds in over the Northeast U.S., the pressure gradient will tighten. Gusty winds are likely Sunday through mid work week, especially on the east coast of Florida. These strong onshore winds will also bring some minor coastal flooding around high tide to the coastal northeast Florida.

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Upper level winds increase across north and central Florida in the wake of a frontal boundary. At the same time, an upper level low in the eastern Gulf enhances wind shear near Invest 99L too . These winds aloft are unfavorable for tropical depression development. Invest 99L merges with a cold front late Saturday and Sunday.

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Tropical characteristics or not, the disturbance is a big rainmaker for some. The heaviest will fall across northeast Florida near the coast from Jacksonville to Daytona Beach. The European model estimates 3-4″+ for Jacksonville and Daytona Beach through midday Monday. It will be an unsettled weekend in central Florida too with periods of rain/storms.

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Elsewhere, Lee is no longer tropical in the north Atlantic. Maria transitions to an extratropical system and will become a remnant low by Saturday evening. It races northeast toward the United Kingdom early this work week. Wind shear will keep a tropical wave near the northeast Caribbean from developing. Heavy rain is still likely the Virgin Islands and Puerto Rico through Sunday. A Flash Flood Watch is in effect through late Sunday. Sadly, these areas are recovering from Irma and Maria.

All eyes are on the Gulf of Mexico and Western Caribbean in early and mid October. Long-range models hint that pressure will be lowering late next week. It’s too early to pin point exactly where.

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Hurricane Maria Generates Swells Along East Coast; Tropical Storm Conditions in the Outer Banks Early Wednesday

Hurricane Maria hangs on Monday evening. The once major hurricane loses its symmetry and deep convection near its core. Maria combats stronger upper levels winds and taps into some cooler waters from upwelling from Jose. As of 5 PM it is a category 1 hurricane with 80 mph. It moves north at 7 mph. At this pace Maria will make its closest pass to the Outer Banks of North Carolina as a strong tropical storm early Wednesday. A strong upper level trough while guide Maria out to sea late in the work week. A Tropical Storm Warning is in effect for North of Duck to the North Carolina/Virginia border and North of Surf City to south of Cape Lookout. A Storm Surge Watch is in effect for Cape Lookout to Duck North Carolina. A mandatory evacuation was ordered from Ocracoke Island and Hatteras Island Monday afternoon.

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Here is the 5 PM advisory. Notice the sharp northeast track after Wednesday. Maria will accelerate out to sea and lose tropical characteristics by Saturday.

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While the center of Maria will pass well east of North Carolina, the tropical storm force wind field is quite large. Tropical storm force winds extend out 200 miles from its center. Sustained winds will approach low-end tropical storm force in the Outer Banks late Tuesday and early Wednesday. Below is the GFS wind speed forecast for early Wednesday morning. Higher gusts are likely. Outer bands will bring 1-2 inches of rain to the region, but this won’t be a big rainmaker.

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Wave heights continue to build as Maria lifts northward in the western Atlantic. Dangerous swells reach the Mid Atlantic and even the Northeast Monday evening. Rough surf will continue through at least mid-week. This enhances the risk for rip currents and beach erosion. A 2-4 foot storm surge is possible from Cape Lookout to Duck North Carolina, including the sound side of the Outer Banks. Coastal flooding is possible starting Tuesday.

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Elsewhere tiny hurricane Lee churns across the north central Atlantic. It weakens some at 5 PM. It is no threat to any land and will stay over the open Atlantic.

As October approaches, all eyes are on the western Caribbean and Gulf of Mexico. Long range models hint that pressure may lower in the western Caribbean during the first week of October. This is in line with climatology this time of year. Water temperatures are in the mid 80s. Our focus shifts to this region and away from the Main Development Region in the central Atlantic in the coming weeks.

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